（1）x/2+y/3=-1 ,x/3+z/4=4 ,y/2+z/4=-4(2)x：y=4：7 ,x：z=3：5 ,x-2y+3z=30(3)x+3y-z=13 ,3x-2y-z=2 ,2x-y+z=-3

已知xyz≥0,x+y+z=1,化简x（2y-z）/(1+x+3y)+y(2z-x) /(1+y+3z) +z(2x-y)/(1+z+3x) 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知（1）X-Y+Z=0 (2)X+2Y-3Z=0 求X:Y:Z 已知x/2=y/3=z/4,求下列各式 （1）(x+y+z)/x (2)(x-y+2x/(x-y-2z) 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. x+y+z=6 x+2y+3z=14 y+1=z 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 已知4x-3y-3z=x-3y+z=0(x、y、z不等于0)(1)求x：y：z （2）求2x+3y-4z/z的值 已知4x-3y-3z=0,x-3y-z=0求(1)x:z的值.（2）x:y:z的值. 分式加减的几道题目求速度1 .(x+y)²/（x-z)(y-z) - (y+z)²/（x-z)(y-z) = 2.2x+3y/x-y+2y/y-x-3y/x-y= matlab解对数方程组[x,y,z]=solve('0.29744*x/(3+0.1*x+y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)))^2','0.79*x/(3+0.1*y+z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.1*y+z)))^2','1.25*x/(3+0.1*z)=(log10((3+x+y+z)/(3+0.1*x+y+z)*(3+y+z)/(3+0.*1y+z)*(3+z)/ 若x+y+z+3=2(根号x+根号y+1+根号z-1）求（x+y+z）y-z 求解一道数学题若x+y+z+3=2(根号x+根号y+1+根号z-1),求（x+y+z)的（y-z）次方 如果,根号x-3+| y-2 |+z^2=2z-1 求 （x+z)^y {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 设x.y.z满足3x=4y=6z（x.y.z都是指数）求证1/z-1/x=1/2y(2）比较3x.4y.6z的大小 已知（x+y-xy）/(x+y+2xy)=(y+z-2yz)/(y+z+3yz)=(z+x-3zx)/(z+x+4zx),且2/x=3/y-1/z,则xyz=?